It can be initially confusing to select a shoe to wear snowshoeing, since you can’t go down to the local store and look at the specific snowshoe boot selection (yet). You can come up with something that will work well if you remember these tips.
Try to get by with the lightest shoe or boot possible. Do not negate the advantage you get with a new pair of high-tech and lightweight snowshoes by wearing heavy boots with them. Snowshoeing is a highly aerobic activity that produces heat and the extra insulation you get from some of the winter boots out there may not be needed snowshoeing. Think about what would be best to wear if you were going to be covering your chosen distance without snowshoes. Except for extreme conditions, footwear that flexes at the ball of the foot is best. Many people snowshoe in lightweight hiking boots or even running shoes.
Match your footwear to your level of exertion, the weather, the amount of loose snow you will be going through, the duration of your trip, and your own metabolism.
Consider using a half to full size larger boot or shoe to accommodate another layer of insulating socks inside. Tight shoes will restrict circulation and lead to cold feet. Make sure your shoes have some type of visible notch or protrusion on the back of the heel where the heel strap of the snowshoe binding can rest so that it does not repeatedly slip off when snowshoeing. Cowboy boots and high heel spikes, with their rounded hell areas, are poor choices for snowshoeing.
Try to use the layering concept for your feet. You want a system that is lightweight and adaptable to a wide range of conditions and use. I currently use the following, listed inside to out: A pair of thin polypro-pylene liner socks, neoprene socks, a running shoe or light hiking boot, a stretchy neoprene cycling over bootie, and then a gaiter or supergaiter. I can use what I need for the intensity, duration and weather conditions of that day, and it all weighs less and is just as warm as big thick pair of boots on cold days.
Everyone is different, with different metabolic rates, blood flow patterns and resistance to cold. You have to pick something that suits you best.
Ankle support is not very important in snowshoeing boots as the snowshoes provide fantastic stability. The snowshoe, not the shoe, provides traction. Canadian leather moccasins actually work well as snowshoe boots…as do old running shoes (you no longer need the thick comfortable midsole as the snow is soft). Some people do well in canvas basketball shoes (covered or sprayed with water repellant fabric).
An old comfortable pair of shoes/boots you already own may work best. Old shoes you already have require no additional expense. Worn tread should not be an issue. Old stretched-out shoes accommodate another pair of socks well, and they are broken in so they will flex well in the cold. The uppers already conform to your feet and there are probably few tight spots. If you get them soaking wet you will not worry about them much. It is worth a try before dropping money on new things.
If you do plan to buy new boots or shoes for snowshoeing look for waterproof uppers (GORE-TEX/climafit). Nylon and synthetics uppers dry faster than leather. Solid nylon uppers are warmer than mesh. Thinsulate is warmer than nothing if you tend to have cold feet. Try to purchase the lightest weight footwear that will suit you needs. You can always treat a pair of non-waterproof boots with spays or waxes (Snowseal or Nikwax) to make them more water-resistant.
You may see some boots (Columbia) and winter shoes (Nike ACG and Adidas) which mention snowshoe specific adaptations, but these all seem too heavy and with weighty excessive traction outsoles to be a true pieces of snowshoe footwear to me. They are designed as multiple use shoes instead of something to wear when snowshoeing.